SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/cars-air-filter-mpg-myth

On a modern fuel-injected car, what does replacing a clogged air filter mainly improve?

Acceleration, not gas mileage, on modern computer-controlled engines.

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  1. Acceleration, not gas mileage ✔
  2. Gas mileage, by about 10%
  3. Nothing at all

Why: Many people think a new air filter saves gas. The Department of Energy says on modern fuel-injected gas engines it does not improve mileage, but it can improve acceleration.

Huh, didn't know that: On an older carbureted vehicle, replacing a clogged filter can improve both mileage and acceleration.

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References

Answer: Acceleration, not gas mileage. Many people think a new air filter saves gas. The Department of Energy says on modern fuel-injected gas engines it does not improve mileage, but it can improve acceleration.

  1. Keeping Your Vehicle in Shape (fueleconomy.gov, US DOE) www.fueleconomy.gov/feg/maintain.jsp
    Replacing a Clogged Air Filter on Modern Cars Improves Performance but Not MPG
    Checked 2026-10-11.

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